If you pay for Amazon Prime month-to-month rather than on a yearly basis, your budget is about to take a hit. On Friday, the online retailer announced that the monthly subscription fee for the Prime service will increase from $10.99 to $12.99 — a jump of 18% — effective immediately. The price of the student monthly plan is also being bumped up from $5.49 to $6.49, but the annual Prime membership will stay the same at $99 a year.

Amazon introduced the monthly subscription back in April 2016 for those who want to take advantage of the two-day free shipping, but don’t want to commit to a year of the service. UPDATE: An earlier version of this article stated that the monthly Prime subscription does not include access to Prime Video. All Prime subscriptions include Prime Video, but there is a standalone Prime Video subscription available as well for $8.99 a month.

Amazon didn’t offer any specific explanation for the price increase, but did release this statement:

Prime provides an unparalleled combination of shipping, shopping and entertainment benefits, and we continue to invest in making Prime even more valuable for our members. The number of items eligible for unlimited Free Two-Day Shipping increased in recent years from 20 million to more than 100 million items. We have expanded Prime Free Same-Day and Prime Free One-Day delivery to more than 8,000 cities and towns.

While there will undoubtedly be customers perturbed by the price hike, some will likely do the math and opt to switch over to the yearly plan going forward. At least, that’s what Amazon is probably hoping they’ll do. The silver lining is that this is the first Prime price hike since 2014, when Amazon increased the yearly subscription from $79 to $99. Hopefully it will be another three or four years before Prime members have to deal with this again.